The present invention relates to mixtures of azo dyes, to their preparation and to their use in the dyeing or printing of semi-synthetic or synthetic hydrophobic fiber materials.
Azo dyes and their use in the dyeing of semi-synthetic or synthetic hydrophobic fiber materials are known. It has been shown, however, that the known dyes do not entirely cover the full range of shades and there is therefore a need for new dyes or dye mixtures that make it possible to obtain the shades lacking hitherto, especially bluish red shades.
It has now been found, surprisingly, that the mixtures according to the invention meet the criteria given above to a considerable degree.
The present invention accordingly relates to a dye mixture comprising
as component (A) at least one dye of formula 
xe2x80x83and
as component (B) at least one dye of formula 
xe2x80x83wherein
R1 is C1-C6alkyl unsubstituted or substituted by hydroxy, cyano, phenyl, acyloxy or 
xe2x80x83it being possible for the alkyl chain from C3 to be interrupted one or more times by oxygen, or is allyl,
R2 is C1-C4alkyl substituted by C1-C4alkoxycarbonyl, or is n-hexyl,
R3 is C1-C4alkyl, and
R4 is hydrogen, halogen, C1-C4alkyl or C1-C4alkoxy.
R1 as C1-C6alkyl is e.g. methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl, tert-butyl, amyl, tert-amyl (1,1-dimethylpropyl), 1,1,3,3-tetramethylbutyl, hexyl, 1-methylpentyl, neopentyl, cyclopentyl, cyclohexyl, or a respective isomer.
R2, R3 and R4 as C1-C4alkyl are methyl, ethyl, propyl, isopropyl, n-butyl, isobutyl, sec-butyl or tert-butyl.
R2 as C1-C4alkoxycarbonyl is e.g. methoxycarbonyl, ethoxycarbonyl, propoxycarbonyl or butoxycarbonyl.
R4 as C1-C4alkoxy is e.g. methoxy, ethoxy, propoxy or butoxy.
R4 as halogen is fluorine, bromine, iodine or preferably chlorine.
R1 is preferably methyl, unsubstituted or cyano-,hydroxy- or acyloxy-substituted ethyl, allyl, cyclohexyl or benzyl.
R2 is preferably a radical of formula xe2x80x94CH2xe2x80x94COOCH3, xe2x80x94CH2xe2x80x94COOCH2CH3, xe2x80x94CH(CH3)xe2x80x94COOCH3 or xe2x80x94CH(CH3)xe2x80x94COOCH2CH3.
R3 is preferably ethyl or isopropyl and especially methyl.
R4 is preferably methyl or methoxy and especially hydrogen or chlorine.
Acyl is preferably formyl, acetyl or propionyl. The ratio of components (A) and (B) in the dye mixtures according to the invention may vary within a wide range, for example from 99:1 to 1:99, especially from 60:40 to 40:60, more especially from 55:45 to 45:55. A dye mixture having a ratio of components (A) and (B) of 50:50 is very especially preferred.
Preference is given to a dye mixture comprising the dyes of formulae (1) and (2) wherein R1 is methyl, unsubstituted or cyano-, hydroxy- or acyloxy-substituted ethyl, allyl, cyclohexyl or benzyl, R2 is a radical of formula xe2x80x94CH2xe2x80x94COOCH3, xe2x80x94CH2xe2x80x94COOCH2CH3, xe2x80x94CH(CH3)xe2x80x94COOCH3 or xe2x80x94CH(CH3)xe2x80x94COOCH2CH3, R3 is methyl, ethyl or isopropyl and R4 is hydrogen, methyl, methoxy or chlorine.
Special preference is given to a dye mixture comprising
as component (A) the dye of formula 
and as component (B) the dye of formula 
Special preference is also given to a dye mixture comprising the dyes of formulae (1) and (2) wherein R1 is ethyl, R2 is n-hexyl, R3 is methyl and R4 is hydrogen.
Very special preference is given to a dye mixture comprising the dyes of formulae (3) and (4) in a ratio of 50:50.
Very special preference is also given to dye mixtures of the dyes of formulae (1) and (2) having CIELAB coordinates a* of from 37 to 60, especially from 55 to 58, and b* of from xe2x88x925 to 25, especially from xe2x88x922 to 20.
The determination of the CIELAB coordinates a* and b* is described in the German standard DIN 6174 xe2x80x9cFarbmetrische Bestimmung von Farbabstanden bei Kxc3x6rperfarben nach der CIELAB-Formelxe2x80x9d (xe2x80x9cColorimetric determination of colour distances in surface colours in accordance with the CIELAB formulaxe2x80x9d) of January 1979. The present invention relates also to the process for the preparation of the dye mixtures of formulae (1) and (2) according to the invention.
They are prepared, for example, as follows: a compound of formula 
is reacted with Br2 and KSCN in acetic acid analogously to a procedure described on pages 57 to 64 of xe2x80x9cDyes and Pigmentsxe2x80x9d, Vol. 38 to form a mixture comprising the compounds of formulae 
the resulting mixture is diazotised in accordance with a customary procedure and then coupled to a coupling component of formula 
R1, R2, R3 and R4 being as defined above.
The diazotisation of the compounds of formulae (51) and (51a) is carried out in a manner known per se, for example with sodium nitrite in an acidic, e.g. hydrochloric-acid-containing or sulfuric-acid-containing, aqueous medium. The diazotisation may, however, also be carried out using other diazotisation agents, e.g. with nitrosylsulfuric acid. In the diazotisation, an additional acid may be present in the reaction medium, e.g. phosphoric acid, sulfuric acid, acetic acid, propionic acid or hydrochloric acid or a mixture of such acids, e.g. a mixture of propionic acid and acetic acid. The diazotisation is advantageously carried out at temperatures of from xe2x88x9210 to 30xc2x0 C., for example from xe2x88x9210xc2x0 C. to room temperature. The coupling of the mixture of the diazotised compounds of formulae (51) and (51a) to the coupling component of formula (52) is likewise effected in known manner, for example in an acidic, aqueous or aqueous-organic medium, advantageously at temperatures of from xe2x88x9210 to 30xc2x0 C., especially below 10xc2x0 C. Examples of acids used are hydrochloric acid, acetic acid, propionic acid, sulfuric acid and phosphoric acid.
The compound of formula (50) is known and can be prepared in a manner known per se.
The coupling component of formula (52) can be prepared in a manner known per se by reacting, for example, a compound of formula 
wherein R1 and R3 are as defined above, with ClCH2COOCH3, ClCH2COOC2H5, ClCH(CH3)COOCH3 or ClCH(CH3)COOC2H5 in the presence of sodium carbonate at elevated temperature.
The dye mixtures according to the invention may also be prepared by simply mixing the dyes of formulae (1) and (2) together.
The dye mixtures according to the invention can be used as dyes in the dyeing and printing of semi-synthetic and, especially, synthetic hydrophobic fiber materials, more especially textile materials. Textile materials composed of blends that contain such semi-synthetic and/or synthetic hydrophobic textile materials can likewise be dyed or printed using the compounds according to the invention.
Semi-synthetic textile materials that come into consideration are especially cellulose 2xc2xd-acetate and cellulose triacetate.
Synthetic hydrophobic textile materials consist especially of linear, aromatic polyesters, for example those of terephthalic acid and glycols, especially ethylene glycol, or condensation products of terephthalic acid and 1,4-bis(hydroxymethyl)cyclohexane; of polycarbonates, e.g. those of xcex1,xcex1-dimethyl-4,4-dihydroxy-diphenylmethane and phosgene, and of fibers based on polyvinyl chloride and on polyamide.
The application of the compounds according to the invention to the textile materials is effected in accordance with known dyeing procedures. For example, polyester fiber materials are dyed in the exhaust process from an aqueous dispersion in the presence of customary anionic or non-ionic dispersants and optionally customary swelling agents (carriers) at temperatures of from 80 to 140xc2x0 C. Cellulose 2xc2xd-acetate is dyed preferably at about from 65 to 85xc2x0 C. and cellulose triacetate at temperatures of up to 115xc2x0 C.
The dye mixtures according to the invention will not stain wool and cotton present at the same time in the dyebath or will stain such materials only slightly (very good reservation), so that they can also be used satisfactorily to dye polyester/wool and polyester/cellulose fiber blend fabrics.
The dye mixtures according to the invention are suitable for dyeing in accordance with the thermosol process, in the exhaust and continuous process and for printing processes. The exhaust process is preferred. The liquor ratio is dependent upon the nature of the apparatus, the substrate and the form of make-up. It may, however, be selected within a wide range, e.g. from 1:4 to 1:100, but is preferably from 1:6 to 1:25.
The said textile material can be in a variety of processing forms, e.g. in the form of fibers, yarns or non-wovens and in the form of woven fabrics or knitted fabrics.
It is advantageous to convert the dye mixtures according to the invention into a dye preparation prior to use. For this purpose, the dye mixture is ground so that its particle size is on average from 0.1 to 10 microns. The grinding can be carried out in the presence of dispersants. For example, the dried dye mixture is ground with a dispersant or is kneaded in paste form with a dispersant and then dried in vacuo or by atomisation. The preparations so obtained can be used, after the addition of water, to prepare printing pastes and dyebaths. For printing, the customary thickeners will be used, e.g. modified or unmodified natural products, for example alginates, British gum, gum arabic, crystal gum, locust bean flour, tragacanth, carboxymethylcellulose, hydroxyethylcellulose, starch or synthetic products, for example polyacrylamides, polyacrylic acid or copolymers thereof, or polyvinyl alcohols.
The dye mixtures according to the invention impart to the mentioned materials, especially to polyester material, level colour shades having very good in-use fastness properties, such as, especially, good fastness to light, fastness to thermofixing, to pleating, to chlorine and to wetting, such as fastness to water, perspiration and washing; the finished dyeings are also distinguished by good fastness to rubbing.
The dye mixtures according to the invention can also be used satisfactorily in the preparation of mixed shades together with other dyes. The dye mixtures according to the invention can be used especially as a red component in a trichromatic dyeing or printing technique.
The dye mixtures according to the invention are also very suitable for dyeing hydrophobic textile material from supercritical CO2.
The present invention relates also to the above-mentioned use of the dye mixtures according to the invention as well as to a process for the dyeing or printing of semi-synthetic or synthetic hydrophobic fiber material, especially textile material, which comprises applying the dye mixture according to the invention to the said material or incorporating it into the material. The said hydrophobic fiber material is preferably textile polyester material. Further substrates that can be treated by the process according to the invention and preferred process conditions can be found above in the detailed description of the use of the dye mixtures according to the invention.
The invention relates also to the hydrophobic fiber material, especially polyester textile material, dyed or printed by the said process.
The dye mixtures according to the invention are also suitable for modern reproduction processes, e.g. thermotransfer printing.
The following Examples serve to illustrate the invention. In the Examples, unless otherwise indicated, parts are parts by weight and percentages are percent by weight. The temperatures are given in degrees Celsius. The relationship between parts by weight and parts by volume is the same as that between grams and cubic centimetres.